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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Automatic Monitoring System for time-dependent dielectric breakdown tests ninety-nine metal-oxide semiconductor capacitors simultaneously. Each breakdown generates voltage spike registered on readouts and indicated by LED. Latching circuit prevents recording of possible subsequent breakdowns in same capacitor. In addition to research use, system could also be adapted for quality control.
The parylene coating process developed during this program consists of (1) obtaining a hybrid cover with a hole in it, (2) sealing of the circuit with a hole in the cover, (3) parylene coating through the hole with the external leads protected from parylene by appropriate fixturing, and (4) sealing of the hole by soldering a pretinned kovar tab. Development of the above process required optimization of the parylene coater parameters to obtain a uniform consistent coating which could offer adequate protection to the circuits, fixture design for packages of various types, determination of the size of the deposition hole, and the amount of dimer charge per run, a process to hermetically seal the deposition holes and establishment of quality control techniques or acceptance criteria for the deposited film.
Tests for studying the basic material are considered and quality control investigations involving preimpregnated materials (prepreg) are discussed. Attention is given to the prepreg area weight, the fiber area weight of prepregs, the resin content, volatile components, the effective thickness, resin flow, the resistance to bending strain, tensile strength, and shear strength. A description of tests conducted during the manufacturing process is also presented, taking into account X-ray methods, approaches of neutron radiography, ultrasonic procedures, resonance methods and impedance studies.
A comparison is made between fracture toughness KIc as measured by recommended ASTM procedures and crack arrest toughness KIa as measured on more than 100 bolt-loaded double-cantilever beam (DCB) specimens from 7075, 7050, and 7049 alloy plates. Close agreement was found between the two values, KIa being on the average less than KIc over a specified range. This indicates that a simplified test based on a bolt-loaded DCB specimen could be used for quality control, lot release, and screening purposes. Measurements of crack length and specimen deflection are all that are required. The specimens do not have to be fatigue precracked, nor is a tensile machine needed.
Test methods require reference materials to standardize and maintain quality control. Various materials have been evaluated as possible reference materials, including a sample of bisphenol A polycarbonate without additives. Screening tests for relative toxicity under various experimental conditions were performed using male mice exposed to pyrolysis effluents over a 200-800 C temperature range. It was found that the bisphenol A polycarbonate served as a suitable reference material as it is available in large quantities, and does not significantly change with time.
Data are presented concerning strength ratios which have been derived from slow bend tests on 0.25-in.-thick precracked Charpy specimens of steels, aluminum alloys, and a titanium alloy for which valid K(Ic) values have been established. The K(Ic) values considered are plane strain fracture toughness values as defined in the ASTM Method E 399-74. The strength ratios are used to develop calibration curves which could be useful in estimating K(Ic) for the purposes of alloy development or quality control.
Bench-mounted and hand-held laser units cut insulation from wires without nipping or scraping conductor. Process eliminates quality control problems and is fast, clean, precise, and repeatable.
Major rotor design criteria are discussed with particular emphasis on those aspects of rotor design that ensure long life component integrity. Dynamic considerations, that necessitate tuning of bladed disk and seal assemblies to avoid excessive vibratory stress at both design and off-design conditions are reviewed as well as low cycle fatigue considerations, which have resulted in detailed analysis procedures to establish part temperature and stress variation throughout an operating cycle and extensive specimen and component fatigue testing to establish safe cyclic operating limits. The frequency, size, and behavior of intrinsic material defects were investigated. Manufacturing process improvements, including the application of increasingly sophisticated inspection techniques and quality control procedures are reviewed in light of their impact on component durability.
Various factors affecting precision of trim and resistor stability were considered. The influence of machine operating parameters on resistor performance was examined and quantified through statistically designed experiments for a Q switched YAG laser system. Laser kerf quality was studied by scanning electron microscopy and related to kerf isolation resistance measurements. A relatively simple production oriented, quality control test is proposed for rapid determination of kerf electrical stability. In addition, the effect of cut design and extent of trim on precision and stability were discussed.
NASA derived technology already in use in the automotive industry include: (1) developments in electronics design, computer systems, and quality control methods for line testing of cars and trucks; (2) a combustion analysis computer program for automotive engine research and development; (3) an infrared scanner and television display for analyzing tire design and performance, and for studying the effects of heat on the service life of V-belts, shock mounts, brakes, and rubber bearings; (4) exhaust gas analyzers for trouble shooting and emissions certification; (5) a device for reducing noise from trucks; and (6) a low cost test vehicle for measuring highway skid resistance. Services offered by NASA to facilitate access to its technology are described.
The empennage component selected for this program is the vertical fin box of the L-1011 aircraft. The box structure extends from the fuselage production joint to the tip rib and includes the front and rear spars. Various design options were evaluated to arrive at a configuration which would offer the highest potential for satisfying program objectives. The preferred configuration selected consists of a hat-stiffened cover with molded integrally stiffened spars, aluminum trussed composite ribs, and composite miniwich web ribs with integrally molded caps. Material screening tests were performed to select an advanced composite material system for the Advanced Composite Vertical Fin (ACFV) that would meet the program requirements from the standpoint of quality, reproducibility, and cost. Preliminary weight and cost analysis were made, targets established, and tracking plans developed. These include FAA certification, ancillary test program, quality control, and structural integrity control plans.
This bibliography lists 782 reports, articles, and other documents introduced into the NASA scientific and technical information system in 1977. The citations, and abstracts when available, are reproduced exactly as they appeared originally in IAA and STAR, including the original accession numbers from the respective announcement journals. Topics cover the management of research and development contracts, production, logistics, personnel, safety, reliability and quality control citations. Includes references on: program, project and systems management; management policy, philosophy, tools, and techniques; decisionmaking processes for managers; technology assessment; management of urban problems; and information for managers on Federal resources, expenditures, financing, and budgeting.
The management of software engineering projects in the aerospace industry was investigated. The survey assessed such features as contract type, specification preparation techniques, software documentation required by customers, planning and cost-estimating, quality control, the use of advanced program practices, software tools and test procedures, the education levels of project managers, programmers and analysts, work assignment, automatic software monitoring capabilities, design and coding reviews, production times, success rates, and organizational structure of the projects.
In many cases it has been found that advances made in one technical field can contribute to other fields. An investigation is in this connection conducted concerning subjects from contemporary NASA programs and projects which might have relevance and potential usefulness to the automotive industry. Examples regarding aerospace developments which have been utilized by the automotive industry are related to electronic design, computer systems, quality control experience, a NASA combustion scanner and television display, exhaust gas analyzers, and a device for suppressing noise propagated through ducts. Projects undertaken by NASA's center for propulsion and power research are examined with respect to their value for the automotive industry. As a result of some of these projects, a gas turbine engine and a Stirling engine might each become a possible alternative to the conventional spark ignition engine.
Report contains preliminary design information for two solar-heating and hot water systems presently under development. Information includes quality control data, special tooling specifications, hazard analysis, and preliminary training program for installation contractors.
Quality control of welded electric wires is improved with easy-to-use tool applying small constant pull force to weldment (typically less than one-twentieth force required to pull weld apart).
Quality-control testing of pulse transformers is speeded up by method for determining rise time and droop. Instead of using oscilloscope and square-wave generator to measure these characteristics directly, method uses voltmeter and sine-wave generator to measure them indirectly in about one-tenth time. Droop and rise time are determined by measuring input/output voltage ratio at just four frequencies.
A program plan, baseline process, measurement program and quality control plan were generated. Cutting operations were completed on the silicon sheet material. The first fabrication run of polycrystalline silicon into solar cells by baseline process was completed. Average conversion efficiency for solar cells fabricated by the baseline process from sheet and measured at air mass zero was 10.4%, compared with the control cells, fabricated from single crystal CZ silicon, whose average conversion efficiency was 12.2%.